Circuit interrupter



M y 1958 H. J. LINGAL ETAL 2,836,684

CIRCUIT INTERRUPTER Filed May 16, 1955 v 3 Sheets-Sheet 1 WITNESSES INVENTORS a HorryJ.Lingol,Bernurd G.Tremb|oy S and Richard Houser May 27, 1958 H. J. LINGAL ET AL 2,336,684

CIRCUIT INTERRUPTER Filed May 16, 1955 s Sheets-Sheet 2 so 64 F I g 2 43 m y 27, 1953 H. J. LINGAL ET AL 2,836,684

CIRCUIT INTERRUPTER Filed May 16, 1955 3 Sheets-Sheet 3 43 Y 60 45 W in United States Patent O cmcurr INTERRUPTER Harry J. Lingal, Bernard G. Tremblay, and Richard Hauser, Pittsburgh, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., 21 corporation of Pennsylvania Application May 16, 1955, Serial No. 508,395

Claims. (Cl. 200-146) This invention relates to circuit 'interrupters and more particularly to contact structures for air circuit interrupters.

An object of the invention is to provide an improved circuit interrupter embodying stationary and moving arcing contacts having auxiliary contact means effective during separation of the arcing contacts to direct the arc toward the arc chamber.

Another object of the invention is to provide a circuit interrupter embodying sets of stationary and moving main and arcing contacts in which the moving arcing contact is separately mounted and remains motionless at its maximum contact pressure during engagement and disengagemer t of the main contacts. 1

Another object of the invention is to provide a circuit interrupter embodying an improved contact structure comprising' separately mounted moving main contact means and moving arcing contact means having means for boldingthe moving arcing contact means stationary until the moving main contact means has moved a predetermined distance in opening direction.

Another object of the invention is to provide a circuit interrupter embodying an improved contact structure whereinvstationary and movable contacts provide a current loop which tends to maintain the contacts closed in the closed contact position, the current loop being shifted to a path where it tends to blow the are away from the contacts upon contact separation.

v The invention, both as to structure and operation, together with additional objects and advantages thereof, will be best understood from the following detailed description thereof when read in conjunction with the accompanying drawings.

In said drawings:

Figure l is a vertical sectional view taken through the center pole ofa three pole circuit interrupter embodying the principles of the invention; v

Fig/2 is an enlarged sectional view of the contact structure for one of the poles of the circuit interrupter;

Fig. 3 is an enlarged view similar to Fig. 2 but showing the contact structure in the position with the main contacts separated and the arcing contacts about to separate; and Y I Fig.;4'is a positional view of a position of Fig. 3 showing the contact arms in the position they assume'whenthe arcing contacts are about to separate.

.Referring to' Fig. 1 of the drawings, the circuit interrupter includes aplurality of pole units each comprising a separable contact structure indicatedgenerally at 11 and an'overcurrent trip'de'vice indicated generally at 13. The contactstructure and tripfdevice for each pole of the circuit interrupter are mounted on separate insulating bases 15 which are rigidly secured to a metal panel 17 by means ofscrews 19. Since thepole units are alike, only one willbe described herein.

The contact structure comprises stationary main contacts 23 and a stationary arcing contact 25 all supported on the; inner end of a U-shaped terminal conductor 27 2,836,684 Patented May 27, 1958 (Fig. l) the legs of which extend through suitable openings in the base 15 and panel 17. Cooperating with the stationary main contacts 23 and the stationary arcing contact 25, respectively, are movable main contacts 29 and a movable arcing contact 31. The movable main contacts 29 are rigidly mounted on a channel-shaped main switch arm 33 pivotally mounted at its lower end on a pin 35 supported in a bracket 37 which is rigidly mounted by means of bolts 39 (only one being shown) on a lower U-shapcd terminal conductor 41. The movable arcing contact 31 is mounted on a contact carrying member 43 rigidly mounted by means of bolts 45 (only one being shown) on the upper or free end of an arcing contact arm 47 which is also pivoted on the pin 35. A flexible conductor 49 has its upper end secured by the bolts 45 to the movable arcing contact and its lower end secured by bolts 51 to the upper end of the main contact arm 33.

The main stationary contacts 23 (Fig. 2) are pivotally supported by means of pivot means 53 in bearing openings in an extension 55 of the terminal 27, and are biased by means of a common spring 57 into engagement with the movable main contacts 29 in the closed position of the circuit interrupter. The stationary arcing contact 25 is pivotally supported by means of pivot means 59 on a bracket 69 secured by means of bolts 62 (only one being shown) to the terminal extension 55, and is biased by means of a spring 64 into engagement with the movable arcing contact 31.

The movable contact structure is normally maintained in the closed position by an operating mechanism indicated generally at 61 (Fig. 1) mounted in a U-shaped frame 63. The frame 63 comprises spaced side members 65 and a connecting cross member 67 and is supported on a platform 69which forms a cross member of a main bracket comprising a pair of spaced side members 71 joined at their outer ends by the cross member or platform 69. The platform. extends substantially across the width of the circuit interrupter and the side members 71 are rigidly secured to the panel 17 on the outer sides of the two outer pole units.

The operating mechanism includes a lever 73 pivotally mounted on a pivot pin 75 supported in the side members of the frame 63. The lever 73 comprises a. pair ofber 77. There is a connecting member 81 for each pole of the circuit interrupter connecting the angle members 77 to the main moving contact member 33 for each pole unit so that, upon operation of the lever 73, the movable contact structure for all these poles move in unison. I

An operating linkage comprising toggle links 83, 35 and 87 is provided to hold the lever 73 and consequently,

the movable contacts in the closed position and to operate the movable contacts to open and closed positions. The toggle link 83 is pivotally connected to lever 73 by a pivot pin 89 and the toggle link 85 is connected by a knee pivot pin 91 to the toggle link 83 and by a knee pivot pin 93 to the toggle link 87. The toggle link 87 is pivotally mounted on a fixed pivot 97 in the frame 63.

The linkage 83, S5, 87 comprises two toggles, one of which 83, 85 functions as a tripping toggle and the other 85, 87 2s a closing toggle. The tripping toggle is normally slightly underset above a line drawn through the centers of the pivot pins 89, 93 and the closing toggle 85, 87 is normally slightly underset below a line drawn through the centers of the pivot pins 91, 97.

' Thetripping toggle 83, 85 is normally biased in'a direction to cause its collapseby components of the springs 57 and 64 and springs 98 (only one being shown) which bias the moving main contact structure for the several poles of the interrupter in opening direction and bias the connecting members 81 toward the left (Fig. l). The tripping toggle 33, 85 is normally prevented from col lapsing by means or" a main latch member 99 pivoted on a pin 100 and connected by a link 101 to the knee pin 91 of the tripping toggle, the link 101 being connected to the latch member 99 by a pin 163.

The main latch 99 is held in latching position by an intermediate latch lever 105 pivoted on a pin 107 in the frame 63. The latch lever 105 carries a latch roller 111 which normally engages the main latch 99 to releasably hold the latter in holding position. The latch lever 105 at its lower end carries a latch member 113 which normally engages a latch member 115 on a lightload latch member 117 pivoted on a pin 119'in the frame 63. The latch lever 105 and the member 117 are biased to their latching positions by a spring 121 tensioned between the posts. Rigidly mounted on the right hand end of member 117 is a trip bar 123 which extends across all of the poles or" the interrupter and has secured thereto an insulating bracket 125 for each pole of the interrupter cooperating with the trip device 13 for the corresponding pole unit.

As long as the main latch 99 is held in latching position by the latching mechanism just described, the tripping toggle 83, 85 will, through the link 101, be held in the position shown in which the interrupter contacts are held in closed position. The closing toggle 35, 87 is normally prevented from collapsing by a shouldered support member 31 pivoted on the pin 107 and biased by a spring 133 into supporting engagement with the knee pin 93 of the closing toggle.

The circuit interrupter is tripped open by operation of the trip device 13 for any pole of the interrupter. The trip device may be of any suitable type, preferably of the type fully disclosed and claimed in copending applicatioirserial No. 514,304, filed June 9, 1955, by M. E. Horn, B. G. Tremblay and F. E. Florschutz, now Patent No. 2,813,170, issued November 12, 1957, and assigned to the assignee of the present invention.

Since the specific trip device does not form a part of this invention, only a brief description thereof is given herein. The trip device comprises a 'U-shaped magnet yoke 135 mounted on the base 15 by means of a screw 137 and having pole pieces 139 (only one being shown) straddling the moving contact arms 33 and 47 so as to be energized by the current fiow therein. delay armature 141 and a short-time-delay armature 143 are provided, both of which are pivoted on a pin 145. The armature 141 is connected by a linkage 147 to a longtime-delay means 149, and a link 151 connects the armature 143 to a short-time-delay means 153. A trip member 155, also pivoted on the pin 145, is disposed to be operated by the trip device to engage'the bracket 125 of its associated pole and actuate the trip bar 123 to effect release of the latch lever 105. When the latch lever 165 is released, the force of the springs 57 and 98 biasing the main movable switch arm 33 in opening direction, and which is transmitted through the connecting members 81 to the lever 73, causes the tripping toggle 83, 85 to collapse upwardly and effects opening movement of the movable main switch arms 33 for all of the poles of the breaker.

Means is provided to hold the movable arcing contact arm 47 stationary with full contact pressure until the movable main contacts have separated a predetermined distance from the stationary main contacts. This means comprises a cam member 155 (Figs. 2 and 3) rigidly secured to the moving arcing arm 47 by means of bolts 157 and nuts 159. Cooperating with a cam surface 161, on the cam member'155, .is a roller 163 rotatable on the pin 80, which pivotally connects'the lever 73'to"thecon-" A lohg-timenectingmemberBl. It will be remembered that the connecting member 81 is connected by the pin 79 to the moving main contact arm 33. In order to open the contacts, the lever 73 moves in a counterclockwise direction about the pivot 75, moving the roller along the cam surface 161. The configuration of the cam surface 161 is such that during the early part of the opening movement and until the roller 163 reaches a point A on the cam member 155, the roller 163 holds the cam member and, hence, the movable arcing contact arm 47 stationary in the fully closed position. During this early movement, the counterclockwise movement of the lever 73 and the leftward movement of the connecting member 81 moves the moving main contact arm 33 in opening direction until the pin 79 engages the arcing contact arm 47. At this time the roller 163 is at the point A, in which position it is shown in Fig. 3. Thereafter, during the opening movement, it moves along an arcuate surface 165 of the cam member 155 which, it will be noted, is struck around the center of the pin 79 with the pin in contact with the arcing contact arm 47. By this means, the two moving contact arms 33 and 4'7 are locked together for unitary movement during the rest of the opening operation.

During opening and closing operations, and in the closed position, good electrical contact is provided at the pivoted end of the movable main contact arm 33 by means of spring biased contact members 167, which are pivoted on the bracket 37 adjacent the terminal conductor '41, and biased into engagement with opposed arcuate surfaces 169 on the contact arm 33 by a spring 171.

The main current path through the interrupter is drom the upper terminal 27, through the main stationary contacts 23, the main moving contacts 29, the main contact arm 33 and through the contact members 167 to the lower terminal 41. A parallel current path is formed from the upper terminal 27 through the stationary arcing contact 25, the moving arcing contact 31, through the flexible conductor 49, the main moving contact arm 33 and the contact members 167 to the lower terminal 41, as indicatedby the arrows in Fig. 3. The magnetic effect of the current loop through the arcing contacts in the closed contact position tends to blow the arcing contacts on, thus permitting the interrupter to carry its rated interrupting current for the duration of the short time delay provided by the short-time-delay means.

The current loop through the arcing contacts would, upon separation of the arcing contacts, tend to blow the arc downward away from the arc chute 173 (Fig. 1). This is prevented and the arc is blown upwardly intothe arc chute by changingthe path of the arcing current at the instant the arcing contacts separate. This is effected by an auxiliary contact 175 (Figs. 2, 3 and 4), on the stationary arcing contact, engaging a fixed secondary contact 177 on the bracket 60, to stop the movement of the stationary arcing contact during an opening operation. As seen'in Fig. 4, when the contact 175 engages the contact 177, the arcing current path changes from that shown by'the arrows in Fig. 2 to the path indicated by the arrows in Fig. 4, so that as the arcing contacts separate, the current loop blows the are drawn between the arcing contacts upwardly into the arc chute (Fig. 1).

After the arcing contacts separate, the main switch arm 33 and the arcing contact arm 47 together move to the fully open position as the tripping toggle 83-85 (Fig. 1) collapses upwardly. The closing toggle 87 does notimmediately collapse following release of the latch mechanism since it is held by the support member 13. During the unlatching movement of the main latch 99, a cam (not shown) thereon'engages the tail of the support member 131 and moves this member in a clockwise direction about its pivot 107 to disengage the shoulder'thereon from beneath the pin 93 whereupon the closing toggle 8587, being no longer supported, collapses downwardly under its own weight and the weight of the moving .armature of the closing solenoid which will be described later. Collapse of the closing toggle 8587 causes the tripping toggle 83-85 to be reset to thrust transmitting position and also effects resetting of the latch mechanism to latching position. The operating mechanism is now in condition for a closing operation.

The circuit interrupter is closed automatically by energization of a closing solenoid 181 (Fig.1) which is in effect either manually or by automatic means. The closingsolenoid 181 comprises'a'fixed magnet yoke 183 and a fixed core member 185 mounted on the underside of the platform 69. A movable armature 187 is attached to the lower end of an operating rod 189 which extends upwardly and has its upper end pivotally connected to the knee pin 93 of the closing toggle 85--87. An energizing coil 191 is supported on the lower end of a supporting bracket 193 having its upper end fastened to the platform 69. I

In the closed position of the interrupter, the armature 187 is held in its raised position (Fig. 1). When the breaker is tripped open, the closing toggle 8587 collapses downwardly permitting the armature 187 to assume its lower or unattracted position. Thereafter, upon energization of the coil 191, the armature 187 is attracted upwardly and acts through the rod 189 to straighten the closing toggle 85-87 and close the contacts.

The action of the contact structure during a closing operation is the reverse of that of the opening operation. As the closing toggle 8587 (Fig. 1) is straightened, the lever 73 is moved in a clockwise direction about its pivot 75 thrusting the connecting member toward the right. At the same time, the roller 163, traveling along the surface 165 of the cam 155, together with the connecting member 81 and the pin 79 locks the main switch member 33 and the arcing contact arm 47 together for unitary movement in closing direction. At the time the roller 163 reaches the point A on the cam 155, the moving arcing contact 31 has engaged the stationary arcing contact and moved it to the fully closed position with full contact pressure applied thereto. At this time, the contacts and the parts are in the position shown in Fig. 3. Continued movement of the lever 73 acts through the connecting member 81 and pin 74 to move the main switch arm to the fully closed position (Fig. 2) the roller 163 moving along the surface 161 of the earn 155 to positively hold the arcing contact arm 47 in the closed position during this last portion of the closing action. At the end of the closing operation, the support 131 (Fig. 1) is moved by the spring 133 to its supporting position under the knee pin 93 of the closing toggle 8587 and, since the tripping toggle 83-85 was reset and relatched when the closing toggle collapsed during the opening operation, the toggle linkage 83 8587 is now held in thrust transmitting position. This, through the lever 73 and connecting member 81, holds the main switch member 33 in the closed position, and by means of the roller 163 and cam 155 holds the arcing contact arm 47 in the closed position.

The invention provides a circuit interrupter having a contact structure in which the moving arcing contact is held stationary in the fully closed position under full contact pressure while the main moving contacts are moved a predetermined distance in opening direction after which the moving main and arcing contacts move in unison to the open position, the stationary and moving arcing contacts being so arranged that at the instant of separation the current path therethrough is shifted to a path wherein the magnetic elfect tends to blow the are drawn between the arcing contacts outwardly into the arc extinguisher.

While the invention has been disclosed in accordance with the provisions of the patent statutes, it is to be understood that various changes in the structural details and arrangement of parts thereof may be made without departing from the spirit of the invention.

' We claim as our invention:

1. In a circuit interrupter, a plurality of stationarycontacts, a plurality of cooperating movable contacts, separate movable switch arms supporting said movable con tacts, operating means operable to move one of said switch arms to open and closed positions comprising a pair of toggle links, a knee pivot connecting said toggle links together, one of said toggle links being mounted on a fixed pivot, a pin pivotally connecting the other of said toggle links to one of said switch arms and disposed to engage the other of said switch arms after a predetermined movement of said one switch arm in opening direction, a separate cam member rigidly secured to the other of said switch arms, a cam surface on said cam member concentric with said fixed pivot, a roller on said knee pivot engaging said cam surface to permit said toggle to move said one switch arm in opening direction until said pin engages said other switch arm while holding said other switch arm in closed'position, a second cam surface on said cam member concentric with said pin when said pin is in engagement with said other switch arm, said second cam surface being engageable by said roller when said pin engages said other switch arm to permit collapse of said toggle while locking said switch arms between said roller and said pin for movement in unison to the open position.

2. In a circuit interrupter, a fixed support member, stationary main and arcing contacts pivotally mounted on said fixed support member, movable main and arcing contacts cooperating with said stationary main and arcing contacts in the closed position to form parallel current paths through said main and arcing contacts, a main movable switch arm supporting said main movable contact, a separate movable switch arm supporting said movable arcing contact, operating mechanism operable to move said movable switch arms to open and closed positions, a cam member on said separate switch arm cooperating with a part movable with said operating mechanism during an opening operation to first hold said separate switch arm in the closed position while said main movable switch arm moves a predetermined distance and then to effect unitary movement of both of said switch arms to open position, and normally open auxiliary contact means comprising a stationary auxiliary contact mounted on said fixed support member at a point remote from the pivot of said stationary arcing contact, a movable auxiliary contact mounted on said stationary arcing contact at the end thereof remote from the pivot of said stationary arcing contact and engageable with said stationary auxiliary contact upon separation of said arcing contacts to move the current path through the arcing contacts away from the pivot of said stationary arcing contact.

3. In a circuit interrupter, a stationary contact structure comprising a fixed conducting support member, a pivoted contact having pivot means pivotally mounting said contact on said support member and biased to prowide contact pressure in the closed position, a fixed secondary contact rigid with said support member at a point remote from said pivot means, a movable contact cooperating with said pivoted stationary contact to draw an are, said contacts forming a current loop extending through said pivot means of said stationary contact the magnetic forces of which current loop force the pivoted stationary contact against the movable contact in the closed position thereof, an auxiliary contact on said pivoted stationary contact remote from said pivot means and engageable with said secondary contact upon separation of said stationary and movable contacts to move said current loop inwardly away from said pivot means to a point remote from said pivot means whereby the magnetic force of said current loop moves the'arc outwardly away from said contacts.

4. In a circuit interrupter, an arc extinguisher, a fixed contact support member, a stationary contact structure adjacent said arc extinguisher comprising a pivoted contact biased to provide contact pressure in the closed position, pivot means pivotally supporting said contact on said fixed support member, a secondary contact rigidly mounted on said fixed support member at a point remote from said pivot means, a movable contact cooperating with said stationary contact to draw ancarc, said stationary and movable contacts forming a current loop through said pivot means the magnetic forces of which loop force the pivoted stationary contact against said movable contact in the closed position thereof, and an auxiliary contact on the end of said pivoted stationary contact remote from said pivot means engaging said fixed secondary contact upon separation of said movable and stationary contacts, said secondary contact and said auxiliary contact when engaged forming a current loop inwardly remote from said pivot means to magnetically force the arc outwardly away from said contacts and toward said are extinguisher.

5. In a circuit interrupter, a fixed contact support member, a stationary contact having oneend pivoted on said fixed support member and the other end'free, pivot means for said stationary contact, a secondarycontact on the freeend of said stationary contactremote fromcsaid pivot means, a movable contact cooperating with said stationary contact to draw .an arc, biasingrrneans biasing said pivoted stationary contact to provide contact pressure in the closed position of said movable contact, operating means operable tomove said movable contact. to open andv closedv positions, said contacts forming a current loop extending through the pivoted end of said stationary contact, the magnetic forces of said current loop forcing said pivoted stationary contact against said movable contact in the closed 'positions, an auxiliary contact on said support member inwardly remote from said pivot means and engaged by said secondary contact on the free end of said pivoted stationarycontact during an opening movement of said movable contact, and said secondary and auxiliary contacts upon separation of said contacts moving said current loop from the pivoted end of said stationary contact tothe free-end thereof so thatthe magnetic forces of said current loop force the arc outwardly away from said contacts.

References Cited in therfile ofithis patent UNITED "STATES PATENTS Scott Nov. 1, 1910 Wood Aug. '31, 1943 

